package com.sunnada.edu.system.pub.util;

/**
 * Cipher class is the type for all other ciphers.
 * @author Marcus Meissner
 * @version $Id: Cipher.java,v 1.1 2010/07/23 19:34:31 qiuzq Exp $
 */

public abstract class Cipher {

  public static Cipher getInstance(String algorithm) {
    Class<?> c;
    try {
      c = Class.forName("platform.com.proComm.commEncrypt." + algorithm);
      return (Cipher) c.newInstance();
    } catch (Throwable t) {
      System.err.println("Cipher: unable to load instance of '" + algorithm + "'");
      return null;
    }
  }

  /**
   * Encrypt source byte array using the instantiated algorithm.
   */
  public byte[] encrypt(byte[] src) {
    byte[] dest = new byte[src.length];
    encrypt(src, 0, dest, 0, src.length);
    return dest;
  }

  /**
   * The actual encryption takes place here.
   */
  public abstract void encrypt(byte[] src, int srcOff, byte[] dest, int destOff, int len);

  /**
   * Decrypt source byte array using the instantiated algorithm.
   */
  public byte[] decrypt(byte[] src) {
    byte[] dest = new byte[src.length];
    decrypt(src, 0, dest, 0, src.length);
    return dest;
  }

  /**
   * The actual decryption takes place here.
   */
  public abstract void decrypt(byte[] src, int srcOff, byte[] dest, int destOff, int len);

  public abstract void setKey(byte[] key);

  public void setKey(String key) {
    setKey(key.getBytes());
  }
}
